The present invention relates to a safety device with bursting knife and diaphragm for limiting the pressure of a fluid. It particularly applies to the protection of installations containing a pressurized fluid (i.e. a liquid or gas) and more specifically the protection of steam generators of sodium-cooled, fast neutron nuclear reactors. It makes it possible to protect such steam generators against the effects of accidental overpressure resulting from a sodium-water reaction and to discharge the products of said reaction.
A safety device with a bursting knife and diaphragm for limiting the pressure of a fluid is known from U.S. Pat. No. 3,872,874.
In this device, the knife is fixed and the diaphragm can only burst after being adequately deformed in the direction of the knife, when the pressure reaches the so-called bursting pressure and which is defined by a presetting of the distance between the knife and the diaphragm. Thus, the operation of this device can only be passive, i.e. it is completely dependent on the development of the pressure level as a function of time in the protected installation.
Such an operation which is only passive is disadvantageous because, for operating reasons (such as the removal of products from the sodium-water reaction in the example given hereinbefore in order to minimize caustic corrosion phenomena) or for reasons of the protection of structures, it may be advantageous to anticipate the bursting of the disk, i.e. to make it burst before the bursting pressure is reached.